You've likely not heard of neuropathy, but you probably know it by its more common term: nerve damage. Peripheral neuropathy is more specifically a painful tingling or burning feeling that afflicts the limbs, usually your hands and feet. Though the side effects of caffeine, such as flushed skin and trembling, can closely mimic the symptoms of peripheral neuropathy, no conclusive connection exists between this disorder and the stimulant in your morning Joe.
Instead, the Mayo Clinic blames this condition on trauma, infection, impaired metabolism and toxic substances. The Neuropathy Association, the leading resource for nerve-related disorders, also makes no mention of caffeine as the cause of peripheral neuropathy.
Confusion about caffeine's role in peripheral neuropathy comes from the fact that it is a stimulant of the nervous system, and peripheral neuropathy is a nerve disease. Drugs.com, a database of drug information, does go so far as to mention peripheral neuropathy by name as a side effect of caffeine. But most leading institutions, such as the Mayo Clinic and the National Institutes of Health, don't mention peripheral neuropathy as a side effect, but rather mention caffeine's likelihood of causing muscle twitches and tremors.
A distinction must be made between two or four cups of brewed coffee, what the American Heart Association considers "average" intake, versus what NIH considers "excessive"--that's 10 8-oz. cups. Serious displays of muscular impairment and other severe side effects, such as excessively elevated blood pressure, are correlated with the amount of caffeine consumed, as well as your sensitivity to the drug's effects.
There have been links established between peripheral neuropathy and another drug: alcohol. According to the Mayo Clinic, alcoholism causes peripheral neuropathy because many heavy drinkers don't eat the way they should, and when they're not eating well, their body is deprived of vital nutrients. One nutrient in particular, vitamin B, is crucial to nerve health.